For uncontrolled tremor, ultrasound instead of brain surgery?

Patients with uncontrolled shaking caused by a condition called essential tremor may get relief with a new noninvasive ultrasound procedure, a study finds.

The movement disorder involves involuntary tremors in the hands or feet, and sometimes the voice is shaky, said Dr. Max Wintermark, a professor of neuroradiology at the Stanford Neuroscience Health Center in Palo Alto, Calif. “It’s called ‘essential’ because we don’t know what is causing it.”

In some cases, essential tremor keeps people from feeding themselves, writing or carrying out other everyday activities. It’s estimated that more than 7 million people have the condition in the United States.

The standard medications, drugs called propranolol and primidone, only help as many as 60 percent of patients, and they lose effectiveness over time. Until now, when drugs failed, doctors could only offer brain surgery — including deep brain stimulation — as a potential treatment, the researchers said.

Forced ultrasound, a noninvasive technique, is “a new treatment option that is available for patients with essential tremor,” said Wintermark, who wasn’t involved in the study. He termed this advance “exciting.”

Based on this trial, the U.S. Food and Drug Administration in July approved the technique to treat essential tremor. Israel-based InSightec, the device maker, funded the research.

Here’s how forced ultrasound works: Sound waves guided by MRI are sent into an area of the brain called the thalamus to kill cells causing the tremor, researchers explain.

“This technology allows you to destroy those tremor cells completely in a noninvasive procedure that takes a day,” said study co-author Dr. Travis Tierney, a pediatric neurosurgeon at Nicklaus Children’s Hospital in Miami.

Previously, doctors might have suggested electrical stimulation, but with that approach, he said, “you have to make an incision and put in a complicated pacemaker system with an electrode in the brain that stays with the patient for the rest of their lives.”

According to Tierney, Medicare and other insurers will cover the ultrasound procedure. He said it’s FDA-approved for those aged 22 and older who have failed medical therapy.

For the study, Tierney and colleagues randomly assigned 76 patients with moderate-to-severe essential tremor who had not responded to medical treatment to focused ultrasound or a sham procedure. Patients completed a quality-of-life questionnaire at the start of the study and periodically for one year.

Neurologists saw videotapes of patients and assessed improvements in tremor, according to the report published Aug. 25 in the New England Journal of Medicine.